Powershell retrieving a variable from a text file - powershell

Question

Is there a way to read a text file C:\test.txt and retrieve a particular value?
ie file looks like this:
serverName=serv8496
midasServer=serv8194
I want to set the value of a variable in my script in some way from this file eg:
$MidasServer= (from file midasServer value)
I will not know the line number where the reference is.
Any way to do this?

Answer 1

Yes, read the file, split each line and assign the split result to the Name and Value parameters:
Get-Content file.txt | Foreach-Object{
$var = $_.Split('=')
New-Variable -Name $var[0] -Value $var[1]
}

Answer 2

If that is exactly how your file appears i.e. a list of key value pairs denoted with a equals sign then you should have a look at ConvertFrom-StringData which
converts a string that contains one or more key and value pairs into a hash table. Because each key/value pair must be on a separate line, here-strings are often used as the input format.
So if a text file contained just the data in your example you could do this to create a hashtable
$Path = "C:\temp\test.txt"
$values = Get-Content $Path | Out-String | ConvertFrom-StringData
$values.midasServer
Where the $values.midasServer would have the value serv8194. No need to know where the properties are in respect to the file. Your input file can also have varying leading and trailing space around the equals sign which will give the exact same result.
Depending on your use case you can take that one step farther and create a custom object from that hashtable
New-Object -TypeName pscustomobject -Property $values
If you have at least PowerShell v3 or higher you can simplify the process (assuming you want a custom psobject)
$values = [pscustomobject](Get-Content $Path -Raw | ConvertFrom-StringData)
$values.midasServer

Answer 3

This is an improvement to the Shay Levy's answer. It does the following.
It ignores commented lines and new lines in the file.txt before
start processing the file. So it resolves the error saying that name
could not be created because it is an empty string.
It splits only on the first occurrence of the character "=".
Therefore you can use any characters in the value field.
It performs Trim() operation in order to remove space characters from the beginning and end of the variable/property. Therefore "VARIABLE=VALUE" and "VARIABLE = VALUE" in the file.txt returns the same.
Set the scope of new variables to "Script". Variables created in the
script scope are accessible only within the script file or module
they are created in. Other options are Global, Local and Private.
You can find a variable scope reference here.
Get-Content file.txt | Where-Object {$_.length -gt 0} | Where-Object {!$_.StartsWith("#")} | ForEach-Object {
$var = $_.Split('=',2).Trim()
New-Variable -Scope Script -Name $var[0] -Value $var[1]
}

Answer 4

This was successful for me:
(input file = filename.txt)
[string] $person 'Joe'
[int] $age 50
[datetime] $dob '06/11/1971'
(commands)
Get-Content filename.txt | ForEach-Object {
$invar = $_.Split(" ").Trim()
Invoke-Expression (Invoke-Command -ScriptBlock {
$($invar[0])+$($invar[1])+'='+$($invar[2])
} )
}
If you know there's a "value", that will contain spaces, i.e. "person "Joe B", just join the values, like so...
Replace this:
        $($invar[0])+$($invar[1])+'='+$($invar[2])
With this:
        $($invar[1])+$($invar[2])+'='+ (-join $($invar[3]),$($invar[4]),$($invar[5]) )